Insects invade every walk of live, from the agricultural fields where our food is grown to the outdoor picnic to the garbage cans waiting for pickup. Billions of insects of many thousands of vanities swarm and fly all over every part of the globe every day. From the dawn of man, creative attempts have repeatedly been made to deal with this problem.
Both to protect crops and animals and maintain public health, many products have been offered over the years to combat insects. It is estimated that as much as ten percent of the food man produces is consumed by insects. In addition to being annoying, insects transmit innumerable diseases, some of which are fatal and can cause epidemics. Due to the present concern over insect-borne diseases, such as lyme disease carried by ticks and West Nile virus carried by mosquitoes, there is an ever increasing need for an environmentally friendly insect repellent, which is effective to repel insects
As is well know, insects breathe by means of tubes that open at the body surface in spiracles. Internally, these tubes divide into very fine branches leading to the internal vital organs. These spiracles are water repellent, but oil may enter them. Accordingly, different types of oils are typically used to enter the spiracles and to damage the internal organs, so the insects will be killed or at least repelled.
There is an important distinction between insecticides and repellents. Insecticides are intended to destroy or kill insects, are generally much stronger than repellents and are toxic to man in varying degrees. Substantially most of the insecticides have to be registered by the Environmental Protection Agency (EPA), as they all typically have some level of toxicity. Many of these insecticides are not biodegradable and some (such as DDT) have been banned from agricultural use due to their harmful ecological effects.
Repellents, however may be defined as substances that cause an insect to turn away—“be repelled.” They are necessarily milder, and are intended merely to “turn away” or “repel” insects, as opposed to actually destroying or killing them. Literally thousands of compositions are know to have some effect in repelling insects.
Essential oil are volatile oils derived from the leaves, stem, flower, or twigs of plants, and usually carrying the odor or flavor of the plant. They have a pungent taste and odor and generally are colorless. Over the years, they have been used widely in perfumery and flavors. Many of these essential oils have insect repellent capability, as is well known in the industry.
Many considerations are involved in creating insect repellents. Attention must be given to toxicity, biodegradability, ecological effect, harshness, skin dessication and skin and eye irritation, among another factors. Many repellents that are environmentally safe and friendly are harsh and are skin and eye irritants, whereas many that are safe for the body are not good for the environment.
In the past, little attention was given to the toxicity of compounds used to control insects. That is no longer the case. Strong control over these products is exercised by the U.S. Environmental Agency (EPA). Most insect repellents that are registered with EPA have warnings to prohibit their use near food or in food-serving places and in waters bearing fish, or that they cannot be applied to children.
It can, therefore, be appreciated that there is an ever growing market demand for environmentally safe insect repellents that actually effectively work to repel insects. The Food & Drug Administration (FDA) has a classification know as “GRAS,” which designates “Generally Regarded As Safe” compounds. Certain essential oils follow into the GRAS category.
Citronella oil is a well-known and widely used insect repellent. The primary component responsible for its repellent properties is β-citronellol, 3,7-dimethyl-6-octen-1-ol, which is a member of the class of compounds known as terpenes.
D-limonene is another insect repellent, although not as well-known and widely used as citronella oil. D-limonene, 1-methyl-4-(1-methylethenyl)cyclohexene, is also a member of the terpene class.
Some insect repellents are on the market, wherein the active insect repellent is an essential oil, such as citronella oil. These products are generally very weak as repellents and have little effective usefulness. The most common effective insect repellents include DEET as the active compound, but these products are not ecologically friendly and are not natural; they also require EPA registration, and are now being limited in their human usage by the EPA.
Accordingly, there is a market demand for a natural insect repellent which is environmentally safe and friendly, as well as being safe for humans.